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The main focus of this work is the effect of the third body on the friction coefficient of the bottom edge tool-chip in spiral milling with internal cooling at high speeds. The maximum pressure of the tool-chip contact and the tool-chip friction factor of the bottom edge are estimated by evaluating the helical milling principle and milling experiments, and the Hertz-Mindlin with bonding discrete element model（DEM）is established and corrected. The friction coefficient of the bottom edge tool-chip in the process of high-speed internal cooling milling is discovered to decrease with an increase in the number of third bodies by examining the discrete element model and the morphology of the machined surface and the bottom edge. The third body increases as spindle speed increases but decreases as pitch increases. The research results provide a reference for the study of tool - chip friction coefficient in high-speed internal cooling helical milling.

As the demand for difficult-to-cut materials (such as titanium alloys, nickel-based alloys, and stainless steels) continues to increase, internally cooled cutting is receiving increasing attention and research due to lowering the temperature of the cutting zone and improving the quality of the machined surface. With the increase of spindle speed, cavitation problem that plagues the development of high-speed fluid machinery may also cause cavitation damage to internally cooled cutting tools. This paper aims to study cavitation in the process of high-speed milling with internal cooling. A cavitation experiment platform for high-speed milling with internal cooling was established. A cavitation experiment was performed on the platform during high-speed milling with internal cooling. In order to facilitate the observation of cavitation during high-speed milling with internal cooling, Al 6063 and C45 were used as the materials of the workpiece and the milling tool, respectively. The experimental results reveal that after the experiment, fish scale cavity pits and cavitation pinholes were formed on the flank face and some machined surfaces of the workpiece. At the same time, the mechanism of cavitation damage was also preliminarily analyzed. This study is beneficial for exploring the cavitation mechanism in future high-speed internally cooled cutting and guiding the rational use of internally cooled cutting.

Accurate modeling of the instantaneous uncut chip thickness is one of the key issues in milling mechanics. Although most current cutting force models take into account the effects of tool deflection and tool run-out, they only consider single-edge continuous milling processes and do not consider processes where multiple edges are simultaneously engaged in milling. Considering the tool runout and tool deflection that affect the end milling process, a novel uncut chip thickness algorithm based on two-flute continuous milling is proposed in this paper, and an analytical force model for actual milling is established. There is no need to use iterative methods, and the predictive power can be obtained by solving a linear system of equations, so the computational cost is greatly reduced. At the same time, stainless steel 316 was processed, and the experimental results showed that the predicted force was in good agreement with the measured force.

In order to improve the positioning accuracy of the machine tool, the position errors compensation is performed on the three-axis vertical machining center. It is noted that the angular errors and straightness errors of X, Y and Z axes of the machine tool are affected by the position errors. Taking Z-axis position errors compensation as an example, the high-precision laser interferometer and ball bar are used to measure the positioning error, angular errors, straightness errors and squareness error before and after Z-axis position errors compensation, and the results are discussed and compared. The results show that with the improvement of the positioning accuracy of the machine tool, the angular errors and straightness errors also improve, but the impact on the squareness error is not significant. There are not any reports on the results in this regard, and further theoretical analysis will be reported later.

A linear motor is a device that converts electrical energy directly into linear motion mechanical energy. This device is of interest and has many applications. A linear motor that does not have a hampered middle of the rotation mechanism has a significantly enhanced linear motion performance. The performance of a linear motor depends on its energy consumption. Reduction of energy consumption can be used to improve the working efficiency, output characteristics, and operation stability of linear motors. In this study, Ansoft Maxwell software is used to simulate the energy consumption of a linear motor. Analysis of a prototype linear motor driven by an electromagnetic drive revealed its energy consumption. At the same time, the distribution and influence factor of cooper and iron loss are also be revealed. It can provide reference for improving the working performance of linear motors.

Cutting temperature is an important factor which directly affects cutting tool wear, cutting tool life, machined surface quality, and accuracy in the high-speed machining (HSM) process. It is very important to study the distribution law of cutting temperature for the HSM process. In this paper, the self-developed embedded temperature measuring tool holder system (ETMTHS) is employed to measure the continuous temperature of carbide end milling tool tip. The dynamic temperature field model of solid cemented carbide milling cutter is established by using heat source method, and the heat flux in power series form is solved by using the particle swarm optimization (PSO) algorithm. At the same time, an optimization algorithm to solve the inverse problem of heat conduction is given. The solution of heat flux is converted into the solution of the optimal value problem. Using optimization algorithm, the inverse heat conduction problem can be solved successfully. The temperature and its gradient distribution of solid cemented carbide milling cutter are obtained by analyzing the continuous milling temperature of ANSYS simulation. The comparison results show a good agreement between the simulation temperature and measuring temperature.

With the increasing spindle speed and the necessity existence of the cutting fluid, inner cooling milling is drawing more and more attention. In order to research the effect of cutting fluid on the inner cooling tool, a 3D finite element simulation that carbide end mills milling AISI304 steel in inner cooling and drying cooling are carried out respectively. Through the simulation, it is found that the temperature difference in cutting in and out of the workpiece in inner cooling milling is more than in drying milling. The cyclic alternation of heating and cooling is harmful to the tool wear and cutting life. And it is verified in the cutting experiments, there is some crack in inner cooling milling at the spindle speed of 10,000 and 12,000 rpm. This simulation results provide a theoretical basis for the generation of thermal crack on the tool surface of high speed milling.

The cutting force is a key factor that affects the milling performance. The performance of a kind of inner cooling mill with double straight channels developed by us was testified with an index of cutting force. Zig-zag milling experiments were done on CNC milling machine. Cutters with different diameters were carried out at different speeds for inner cooling and outer cooling. The average peak cutting forces per tooth were picked up. The results showed that forces of the outer cooling had been greater than that of inner cooling, and the bigger of the cutter, the more significant of their comparison, which means that inner cooling should be better than outer cooling, and the performance of the cutter was worthy. This work might play important roles in various cutting manufacturing factories and in milling research where inner cooling milling could be used instead of outer cooling.